Print Number input by user is a prime or not using C language

/*Value is prime number or nor*/

#include<stdio.h>  //include header file

void main()
{
    int a,p;
    printf("enter the number");
    scanf("%d",&p);
     a=2;
     while(a<=p-1)
        {
          if(p%a==0)
           {
           
 printf("its not a prime no. ");
            break;
           }  
          a++;
        }// end of while loop
          if(a==p)
          {
           printf("its a prime no.");
          }
} //end of main